A marine surveyor (also referred to as a "yacht & small craft surveyor", "gasoline engine surveyor", diesel engine surveyor", "hull & machinery surveyor" and/or "cargo surveyor") is a person who inspects, surveys, or examines marine vessels in order to assess damage, inspect aberrations, or monitor their condition and that of any cargo on board. Marine surveyors also inspect equipment intended for new or existing vessels to ensure compliance with various standards or specifications. Marine surveys typically include the structure, machinery, and equipment (navigational, safety, radio, etc.) in addition to the general condition of a vessel and/or cargo. They also involve judging materials on board and their condition. Though a largely unregulated profession, marine surveyors are generally trained specifically for the role and usually selected after thorough evaluation procedures. Their duties apply to a wide range of seafaring vessels.

Marine surveying is closely associated with marine insurance, damage and salvage, and accident and fraud investigation as insurers generally rely on the specific training and skills of a marine surveyor to perform a detailed assessment of the condition of a vessel. Marine surveyors may be hired on a fee basis by customers seeking insurance directly and maintain professional autonomy in order to provide an unbiased view. Independent marine surveyors are often employed by the clients of marine insurers to provide evidence in support of damage claims made against the insurer. Insurance companies cannot require customers to use specific marine surveyors and risk legal scrutiny and potential recourse if they impose surveyor requirements.

Marine surveyors use many credentials, letters, and terms such as "accredited," "certified," "qualified," "USSA," "ACMS," "AMS," "CMS," etc. There are many ways to train to become a marine surveyor including taking correspondence courses, apprenticing, and/or utilizing prior marine experience. Marine surveyors pursue their profession independently of required organizations, and there is currently no national or international licensing requirement for marine surveyors. The United States Coast Guard U.S. Coast Guard does not approve or certify marine surveyors; National Association of Marine Surveyors was founded in 1962 and requires members to adhere to strict survey guidelines. All association terms and initials represent training and certification by private organizations, and the end users of boats seeking to comply with their insurance company's underwriting process dictate surveyor demand.

Marine surveying continues to be a largely unregulated industry, allowing individuals from various backgrounds to practice as surveyors. The profession generally involves a working knowledge of the ship's electrical and mechanical systems, and a fundamental understanding of boat design and construction. Moreover, it is customary for marine surveyors to carry errors and omissions insurance, also referred to as professional indemnity insurance, as a form of protection against potential liabilities.

A marine surveyor who is a member of a professional body such as the Society of Accredited Marine Surveyors (USA) or the International Institute of Marine Surveying is more likely to be hired by a client.

When it comes to defining the qualities and qualifications of a marine surveyor, a memorandum of 1834 states:

“The utmost care and discrimination have been exercised by the Committee in the selection of men [and women] of talent, integrity, and firmness as Surveyors, on whom the practical efficacy of the system and the contemplated advantages must so materially depend; the Committee has in their judgment appointed those persons only…who appeared to them to be most competent to discharge the important duties of their situations with fidelity and ability, and to ensure strict and impartial justice to all parties whose property shall come under their supervision.”

— Classification societies – their key role – IACS, 2012